U.S. patent application number 10/742504 was filed with the patent office on 2005-06-23 for toaster using infrared heating for reduced toasting time.
This patent application is currently assigned to HP Intellectual Corporation. Invention is credited to Cavada, Luis, Krasznai, Charles.
Application Number | 20050132900 10/742504 |
Document ID | / |
Family ID | 34678469 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050132900 |
Kind Code |
A1 |
Cavada, Luis ; et
al. |
June 23, 2005 |
Toaster using infrared heating for reduced toasting time
Abstract
A toaster uses radiant heat at infrared wavelengths optimized
for producing rapid and uniform toasting of a food product. The
infrared wavelengths of the radiated heat are selected for optimum
speed and quality (browning and moisture content) of the food
product. The selected infrared wavelengths of the radiated heat may
also effectively defrost a food product. Defrosting of the food
product by the infrared radiated heat adds very little time in
obtaining a desired toast color to the food product. A plurality of
infrared wavelengths of radiated heat may also be used, wherein the
plurality of infrared wavelengths are selected for optimal heat
penetration and surface browning of the food product. Shorter
wavelengths for browning and slightly longer wavelengths to
penetrate the food product for evaporating the moisture therein to
allow surface browning by the shorter wavelengths. In addition, the
heating energy within the toaster may be further elongated (longer
wavelengths) once the infrared radiation is re-radiated off of
reflectors within the toaster. The wavelengths of infrared radiated
heat may be from about 1 to about 3 microns, and preferably from
about 1.96 to about 2.5 microns, and most preferably at about 2.11
microns.
Inventors: |
Cavada, Luis; (Miami,
FL) ; Krasznai, Charles; (Bridgeport, CT) |
Correspondence
Address: |
Baker Botts L.L.P.
One Shell Plaza
910 Louisiana Street
Houston
TX
77002-4995
US
|
Assignee: |
HP Intellectual Corporation
|
Family ID: |
34678469 |
Appl. No.: |
10/742504 |
Filed: |
December 18, 2003 |
Current U.S.
Class: |
99/389 |
Current CPC
Class: |
A47J 37/0807
20130101 |
Class at
Publication: |
099/389 |
International
Class: |
A47J 037/08 |
Claims
What is claimed is:
1. An apparatus for toasting a food product, comprising: a toasting
chamber adapted for receiving a food product to be toasted, the
toasting chamber having first and second sides; a first infrared
heater located on the first side of the toasting chamber; a second
infrared heater located on the second side of the toasting chamber;
a first radiant heat reflector located on the first side of the
toasting chamber, wherein the first infrared heater is located
between the toasting chamber and the first radiant heat reflector;
and a second radiant heat reflector located on the second side of
the toasting chamber, wherein the second infrared heater is located
between the toasting chamber and the second radiant heat reflector;
wherein the first and second infrared heaters emit infrared radiant
heat at a wavelength optimized for toasting of the food
product.
2. The apparatus of claim 1, wherein the toasting chamber has
centering guides for positioning the food product between the first
and second infrared heaters.
3. The apparatus of claim 2, wherein the centering guides are
comprised of wires forming the first and second sides of the
toasting chamber.
4. The apparatus of claim 2, wherein the centering guides are
outwardly biased.
5. The apparatus of claim 1, wherein the first and second infrared
heaters are electrically conductive filaments adapted to pass a
desired amount of electric current therethrough.
6. The apparatus of claim 5, wherein the electrically conductive
filaments are a composition of nickel (Ni) and iron (Fe).
7. The apparatus of claim 5, wherein the electrically conductive
filaments are comprised of a composition of nickel (Ni) and
chromium (Cr).
8. The apparatus of claim 5, wherein the electrically conductive
filaments are comprised of a composition of nickel (Ni), chromium
(Cr) and iron (Fe).
9. The apparatus of claim 5, wherein the electrically conductive
filaments are comprised of a composition of iron (Fe), chromium
(Cr) and aluminum (Al).
10. The apparatus of claim 1, wherein each of the first and second
infrared heaters comprise an electrically conductive filament
inside of a quartz glass tube.
11. The apparatus of claim 10, wherein the quartz glass tube is
clear.
12. The apparatus of claim 10, wherein the quartz glass tube is
chemically etched so as to pass a desired infrared wavelength from
the electrically conductive filament.
13. The apparatus of claim 10, wherein the quartz glass tube has
extruded grooves therein so as to pass a desired infrared
wavelength from the electrically conductive filament.
14. The apparatus of claim 1, wherein the first and second radiant
heat reflectors reflect radiant heat from the first and second
infrared heaters onto the food product surfaces facing the first
and second sides, respectively, of the toasting chamber.
15. The apparatus of claim 14, wherein the first and second radiant
heat reflectors are optimized to evenly distribute radiant heat
onto surfaces of the food product.
16. The apparatus of claim 1, wherein the infrared wavelength is
from about 1 to about 3 microns.
17. The apparatus of claim 1, wherein the infrared wavelength is
from about 1.96 to about 2.5 microns.
18. The apparatus of claim 1, wherein the infrared wavelength is
about 2.11 microns.
19. The apparatus of claim 1, wherein the infrared wavelength
comprises a plurality of infrared wavelengths optimized for
toasting of the food product.
20. The apparatus of claim 14, wherein the reflected radiant heat
is at a longer infrared wavelength than the infrared wavelength of
the radiant heat from the first and second infrared heaters.
21. The apparatus of claim 10, further comprising a gold coating
over a portion of the quartz glass tube, wherein the gold coated
portion is on the distal side of the quartz glass tube from the
food product.
22. The apparatus of claim 1, further comprising a food product
ejector having a first position and a second position, wherein when
in the first position the food product is positioned inside the
toasting chamber and when in the second position the food product
is ejected from the toasting chamber.
23. The apparatus of claim 1, further comprising a housing, wherein
the housing encloses the toasting chamber, the first and second
infrared heaters, and the first and second radiant heater
reflectors.
24. The apparatus of claim 23, further comprising toasting controls
located on the housing.
25. An apparatus for toasting a food product, comprising: a
plurality of toasting chambers, each of the plurality of toasting
chambers having a first side and a second side and each of the
plurality of toasting chambers is adapted for receiving a food
product to be toasted; a first infrared heater for plurality of
toasting chambers and located on the first side thereof; a second
infrared heater for the plurality of toasting chambers and located
on the second side thereof; a first radiant heat reflector located
on the first side of the plurality of toasting chambers, wherein
the first infrared heater is located between the plurality of
toasting chambers and the first radiant heat reflector; and a
second radiant heat reflector located on the second side of the
plurality of toasting chambers, wherein the second infrared heater
is located between the plurality of toasting chambers and the
second radiant heat reflector; wherein the first and second
infrared heaters emit infrared wavelength radiant heat at a
wavelength optimized for toasting of the food product in each of
the plurality of toasting chambers.
26. The apparatus of claim 25, further comprising first and second
infrared heaters for each of the plurality of toasting
chambers.
27. The apparatus of claim 25, further comprising first and second
radiant heat reflectors for each of the plurality of toasting
chambers.
28. A method for toasting a food product with infrared radiant
heat, said method comprising the steps of: evaporating moisture
from and browning surfaces of a food product in a toasting chamber
with radiant heat at a first infrared wavelength emitted from
infrared heaters located on each side of the food product and
radiant heat at a second infrared wavelength reflected from radiant
heat reflectors located on each side of the food product wherein
the infrared heaters are located between the radiant heat
reflectors and the food product.
29. The method of claim 28, wherein the second infrared wavelength
is longer than the first infrared wavelength.
30. The method of claim 29, wherein the radiant heat at the second
infrared wavelength penetrates deeper into the food product than
the radiant heat at the first infrared wavelength.
31. The method of claim 29, wherein the radiant heat at the second
infrared wavelength evaporates the moisture from the food product
fast than the radiant heat at the first infrared wavelength.
32. The method of claim 29, wherein the radiant heat at the first
infrared wavelength browns the food product surface.
33. The method of claim 28, further comprising the step of
defrosting the food product with the radiant heat.
34. The method of claim 28, wherein radiant heat at the first and
second infrared wavelengths are reflected from the radiant heat
reflectors onto the food product.
35. The method of claim 28, further providing the step of emitting
radiant heat from the infrared heaters onto the food product at a
first plurality of infrared wavelengths.
36. The method of claim 28, further providing the step of
reflecting radiant heat from the radiant heat reflectors onto the
food product at a second plurality of infrared wavelengths.
37. The method of claim 28, wherein the first infrared wavelength
is selected for substantially optimum browning of the food
product.
38. The method of claim 28, wherein the second infrared wavelength
is selected for substantially optimum evaporation of moisture from
the food product.
39. The method of claim 28, wherein the first infrared wavelength
is from about 1 to about 3 microns.
40. The method of claim 28, wherein the first infrared wavelength
is from about 1.96 to about 2.5 microns.
41. The method of claim 28, wherein the first infrared wavelength
is about 2.11 microns.
42. The method of claim 28, wherein the first infrared wavelength
comprises a first plurality of infrared wavelengths.
43. The method of claim 28, wherein the second infrared wavelength
comprises a second plurality of infrared wavelengths.
Description
BACKGROUND OF THE INVENTION TECHNOLOGY
[0001] 1. Field of the Invention
[0002] The present invention relates to electric toasters, and more
specifically, to an infrared heated electric toaster having reduced
toasting time and improved browning consistency.
[0003] 2. Background of the Related Technology
[0004] Toasting of food products, e.g., breads and pastries,
requires that moisture be removed therefrom so that the surface of
the food product will turn brown upon further application of heat
thereto. This has generally required several minutes of time for a
food product that is relatively fresh (high moisture content). Over
the years there -have been many attempts at finding ways to speed
up toasting of food products. Toaster appliances employing various
technologies, e.g., calrods, mica card heating elements, halogen
high intensity light, and, in addition, higher power heating
elements have been used, however, all have fallen short of
consumer's expectations. With the toaster appliances used in the
past, there were usually some tradeoffs made by the consumer in
order to gain faster toasting speed. Consumers might comprise
toasting quality, safety, etc., in favor of speed.
[0005] Therefore, a problem exists, and a solution is required for
improving the speed and quality of toasting food products.
SUMMARY OF THE INVENTION
[0006] The present invention remedies the shortcomings of present
toasting technologies by providing a toaster using radiant heat at
infrared wavelengths optimized for producing rapid and uniform
toasting of a food product. The infrared wavelengths of the
radiated heat are selected for optimum speed and quality (browning
and moisture content) of the food product. The selected infrared
wavelengths of the radiated heat may also effectively defrost a
food product. Defrosting of the food product by the infrared
radiated heat adds very little time in obtaining a desired toast
color to the food product. A typical food product toasting time for
the present invention may be about one minute.
[0007] The invention may emit a plurality of infrared wavelengths
of radiated heat, wherein the plurality of infrared wavelengths are
selected for optimal heat penetration and surface browning of the
food product, e.g., shorter wavelengths for browning and slightly
longer wavelengths to penetrate the food product for evaporating
the moisture therein to allow surface browning by the shorter
wavelengths. In addition, the heating energy within the toaster may
be further elongated (longer wavelengths) once the infrared
radiation is re-radiated off of reflectors within the toaster. The
wavelengths of infrared radiated heat may be from about 1 to about
3 microns, and preferably from about 1.96 to about 2.5 microns, and
most preferably at about 2.11 microns.
[0008] According to exemplary embodiments of the invention, the
infrared wavelength radiation emitting heaters may be cylindrical
and may comprise any type of material that can be used for
resistance heating and is capable of emitting heating energy at
infrared wavelengths, e.g., metal alloy filament materials such as,
for example but not limited to, Ni Fe, Ni Cr, Ni Cr Fe and Fe Cr
Al, where the symbols: Ni represents nickel, Fe represents iron, Cr
represents chromium, and Al represents aluminum. The infrared
wavelength emitting filament material may either be exposed or
preferably enclosed within a high temperature infrared wavelength
transparent tube, such as for example, a high temperature quartz
tube, e.g., 99.9 percent pure quartz (SiO.sub.2), and may be clear,
chemically etched, or have extruded grooves therein depending upon
the desired infrared wavelength(s) to be emitted. The filament
material may be heated by an electric current, alternating or
direct, to a temperature sufficient for the emission of energy at a
desired infrared wavelength(s). The infrared wavelength(s) emitted
from the heater may be changed by changing the voltage applied to
the filament material.
[0009] Some of the infrared wavelength energy may be directed
toward the surface of the food product from heat reflectors located
about or proximate, e.g., the infrared wavelength energy emitter
(source) is located between the heat reflector and the food product
being toasted. The heat reflectors may be designed so as to evenly
distribute the infrared wavelength energy over the surface of the
food product for consistent browning thereof. The emitted infrared
wavelengths that are radiated directly onto the surface of the food
product may be selected for optimal browning of the food product,
and the infrared wavelength energy reflected by the heat reflectors
may be at longer infrared wavelengths than the directly radiated
infrared wavelength energy. The longer infrared wavelength energy
will penetrate deeper into the food product to aid in removing
moisture therefrom before surface browning occurs. The heat
reflectors may be fabricated from aluminized steel, bright chrome
plated metal and the like.
[0010] A gold coating, which is a very efficient reflector of
infrared wavelengths, may also be placed over a portion of the
quartz tube of the heater. This gold coating may be used to direct
infrared wavelength energy as desired, e.g., toward the surface of
the food product, and reduce the amount of infrared wavelength
energy from the side of the quartz tube opposite the surface of the
food product. Thus the gold coating will substantially reduce the
infrared wavelength radiation in directions that are not useful for
heating and browning of the food product. In addition, the gold
coating helps reduce the temperature of surfaces behind the gold
coating. By reducing infrared wavelength energy from surfaces not
useful for toasting, e.g., facing toaster housing surfaces, the
metallic housing of a toaster product may be cool to the touch. The
gold coating may be of any thickness, preferably about one micron
in thickness.
[0011] According to an exemplary embodiment of the invention, a
toaster comprises a toasting chamber adapted to receive a food
product, e.g., bread, pastries, bagels, English muffins, biscuits,
waffles, etc., infrared wavelength emitting radiant heat sources
located on either side of the toasting chamber, and heat reflectors
proximate or adjacent to the infrared wavelength heat sources, the
infrared wavelength heat sources advantageously being located
between the toasting chamber and the reflectors. The toaster may
have an ejector mechanism located at the bottom of the food product
toasting chamber, the ejector adapted to expel the food product
from the toasting chamber when toasting thereof is complete. An
enclosure surrounds the food product toasting chamber, infrared
wavelength heat sources and heat reflectors. Controls for the
toaster may also be attached to the enclosure, and/or be an
integral part thereof. The food product toasting chamber may be
adapted to receive one or more items of the food product, e.g.,
slice(s) of bread.
[0012] It is contemplated and within the scope of the present
invention that more than one food product toasting chamber may be
provided in a toaster. Each of the toasting chambers may
advantageously be independently controllable, e.g., different
toasting settings for each chamber. Each of the more than one food
product toasting chambers may have associated infrared wavelength
heat sources on either side of the respective toasting chamber, and
heat reflectors may be adjacent to each of these infrared
wavelength heat sources, the infrared wavelength heat sources being
located between the respective toasting chamber and the respective
reflectors. It is also contemplated and within the scope of the
invention that longer wavelength infrared radiant energy emitting
heat sources and/or from the heat reflectors may be used to improve
the rate of moisture evaporation of the food product so as to allow
even faster surface browning thereof.
[0013] A technical advantage of the present invention is faster
toasting of food products. Another technical advantage is more even
browning of toasted food products. Still another technical
advantage is faster and more even toasting of a variety of food
products, e.g., different types of breads and pastries. Yet another
advantage is good toast color shading on the surface while
retaining a substantial portion of the moisture content of the food
product. Still another technical advantage is defrosting and
toasting of frozen food products. Still another technical advantage
is uniform toast shades over non-uniform width food products. Yet
another advantage is using longer infrared wavelengths in
combination with the selected browning infrared wavelengths for
improving the rate of moisture evaporation of the food product so
as to allow even faster surface browning thereof. Other technical
advantages should be apparent to one of ordinary skill in the art
in view of what has been disclosed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] A more complete understanding of the present disclosure and
advantages thereof may be acquired by referring to the following
description taken in conjunction with the accompanying drawings
wherein:
[0015] FIG. 1 is a schematic elevational view of a cutaway section
of an infrared toaster, according to an exemplary embodiment of the
present invention;
[0016] FIG. 2 is a schematic top view of the infrared toaster
illustrated in FIG. 1;
[0017] FIG. 3 is a schematic top view of an infrared toaster having
greater capacity, according to another exemplary embodiment of the
present invention;
[0018] FIG. 4 is a schematic top view of an infrared toaster having
even greater capacity, according to yet another exemplary
embodiment of the present invention; and
[0019] FIG. 5 is a schematic elevational view of the front controls
of the infrared toaster, according to the exemplary embodiments of
the present invention.
[0020] The present invention may be susceptible to various
modifications and alternative forms. Specific exemplary embodiments
thereof are shown by way of example in the drawing and are
described herein in detail. It should be understood, however, that
the description set forth herein of specific embodiments is not
intended to limit the present invention to the particular forms
disclosed. Rather, all modifications, alternatives, and equivalents
falling within the spirit and scope of the invention as defined by
the appended claims are intended to be covered.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0021] Referring now to the drawings, the details of exemplary
embodiments of the present invention are schematically illustrated.
Like elements in the drawings will be represented by like numbers,
and similar elements will be represented by like numbers with a
different lower case letter suffix.
[0022] Referring now to FIG. 1, depicted is a schematic elevational
view of a cutaway section of an infrared toaster, according to an
exemplary embodiment of the present invention. The infrared
toaster, generally represented by the numeral 100, comprises
infrared wavelength emitting radiant heat sources (hereinafter IR
heaters) 102 and 104, radiant heat reflectors 106 and 108, a
toasting chamber 110 for a food product (not shown), food product
centering guides 112, a food product ejector 114, and a toaster
housing 116. The centering guides 112 may be outwardly biased with
springs 118. The centering guides 112 may be wires and the like.
The ejector 114 is adapted, in a first position, to support the
food product (not shown) inside the toasting chamber 110 during
toasting thereof, and to eject (push up), in a second position, the
toasted food product from the toasting chamber 110.
[0023] The IR heaters 102 and 104 are positioned so as to emit
infrared radiant heat directly onto the surface of the food product
located in the toasting chamber 110. The reflectors 106 and 108 are
shaped so as to reflect onto the food product in the toasting
chamber 110, infrared radiant heat from the IR heaters 102 and 104.
It is contemplated and within the scope of the invention that the
IR heaters 102 and 104 may have any shape or form that
advantageously directs infrared radiant heat into the food product
in an even and uniform manner. The infrared radiant heat
reflected-from the reflectors 106 and 108 may be at a longer
wavelength than the directly emitted infrared radiant heat from the
IR heaters 102 and 104. This longer wavelength infrared radiant
heat penetrates deeper into the food, thus shortening the moisture
evaporation time of the food product before surface browning may
occur. The wavelengths of infrared radiated heat may be from about
1 to about 3 microns, and preferably from about 1.96 to about 2.5
microns, and most preferably at about 2.11 microns.
[0024] The IR heaters 102 and 104 may be a filament 124 whereby
electrical current is passed through the filament so as to heat the
filament to a temperature at which a desired wavelength of infrared
energy is radiated therefrom. The IR heaters 102 and 104 may
radiate a plurality of wavelengths of infrared energy as well as
wavelengths of visible light. Material for and electrical current
through the IR heaters 102 and 104 are selected so that the heaters
produce predominantly the desired infrared wavelength or
wavelengths for toasting of the food product. The filaments 124 of
the IR heaters 102 and 104 may be comprised of any type of material
that can be used for resistance heating and is capable of emitting
heating energy at infrared wavelengths, e.g., metal alloy filament
materials such as, for example but not limited to, Ni Fe, Ni Cr, Ni
Cr Fe and Fe Cr Al, where the symbols: Ni represents nickel, Fe
represents iron, Cr represents chromium, and Al represents
aluminum. The filament 124 may either be exposed or preferably
enclosed within a high temperature infrared wavelength transparent
tube, such as for example, a high temperature quartz tube 126. The
quartz tube 126 may be clear, chemically etched, or have extruded
grooves therein depending upon the desired infrared wavelength to
be emitted therethrough. Electrical current through each filament
124 of the IR heaters 102 and 104 may preferably be about five
amperes at about 120 volts, resulting in a power draw for each of
the IR heaters 102 and 104 of about 600 watts. Thus, the toaster
100 may use a total of about 1200 watts of power which is well
within the rating of a standard 15 or 20 ampere, 120 volt wall
receptacle in a home or business, e.g., kitchen receptacle. It is
contemplated and within the scope of the present invention that
other operating voltages and currents may be used so long as the
desired infrared wavelength(s) of radiant heat energy is
produced.
[0025] The housing 116 may be metal and/or plastic. The housing 116
is open above the toasting chamber 110 so that the food product may
be inserted into the toasting chamber 110 in a direction 120.
Toasting controls 502 (see FIG. 5) for the toaster 100 may be
located on the housing 116. A gold coating 122 may be applied to
the quartz glass tubes 126 for reflecting the infrared wavelength
energy away from the portions of the quartz glass tubes 126 that do
not substantially contribute to the radiant heating and browning of
the food product. The gold coating 122 will help in reducing the
surface temperature of the housing 116. In addition, an air space
between the housing 116 and the reflectors 106 and 108 also aid in
reducing the surface temperature of the housing 116 during toasting
of the food product.
[0026] Referring now to FIG. 2, depicted is a schematic top view of
the infrared toaster illustrated in FIG. 1. The food product 230 is
located in the toasting chamber 110. More than one piece of the
food product 230 may be placed into the toasting chamber 110,
depending upon the size thereof.
[0027] Referring now to FIG. 3, depicted is a schematic top view of
an infrared toaster having greater capacity, according to another
exemplary embodiment of the present invention. The toaster 100a has
at least two toasting chambers 310a and 310b into which food
products 230a and 230b may be inserted, respectively. Either a
single pair of IR heaters (e.g., 102 and 104 of FIG. 1) may be
positioned on either side of the food products 230a and 230b, or
individual pairs of IR heaters and reflectors may be used for each
of the two toasting chambers 310a and 310b.
[0028] Referring now to FIG. 4, depicted is a schematic top view of
an infrared toaster having even greater capacity, according to yet
another exemplary embodiment of the present invention. The toaster
100b has at least two toasting chambers 410a and 410b into which a
plurality of food products 230a-230b and 230c-230d may be inserted,
respectively. Either a single pair of IR heaters (e.g., 102 and 104
of FIG. 1) for each of the toasting chambers 410a and 410b may be
positioned on either side of the food products 230a-230b and
230c-230d, respectively, or individual pairs of IR heaters and
reflectors may be used for each of the plurality of food products
230a-230c.
[0029] Referring now to FIG. 5, depicted is a schematic elevational
view of the front controls of the infrared toaster, according to
the exemplary embodiments of the present invention. A control panel
540 may be located anywhere on the housing 116 so long as the
controls of the panel 540 are easy to use. The controls of the
panel 540 may be used to set the desired toast color and the like.
Also contemplated may be a control for causing the ejector 114 to
manually ejecting the food product 230 from the toasting chamber
110.
[0030] The invention, therefore, is well adapted to carry out the
objects and to attain the ends and advantages mentioned, as well as
others inherent therein. While the invention has been depicted,
described, and is defined by reference to exemplary embodiments of
the invention, such references do not imply a limitation on the
invention, and no such limitation is to be inferred. The invention
is capable of considerable modification, alteration, and
equivalents in form and function, as will occur to those ordinarily
skilled in the pertinent arts and having the benefit of this
disclosure. The depicted and described embodiments of the invention
are exemplary only, and are not exhaustive-of the scope of the
invention. Consequently, the invention is intended to be limited
only by the spirit and scope of the appended claims, giving full
cognizance to equivalents in all respects.
* * * * *